Method of detinning.



8. 0 9 1, 1| n.0 R. A M D E T N E T4 A Di. vm .R R E P `Q METHOD OF'DETINNING. Arrmoulol FILED qu. 1907.

,will QHWTWH- ffornejd escribed in full detail herein,

.of the processfit may in' thev successful detinnlng of tln scrapit is necessaryT not only to recover the tin steel,

' scrap',

"treatment before being lieta. This treatment UNITED ySTATES PATENT OFFICE.

ELMER A. SPERRY, OF BROOKLYN, YORK.

METHOD F DETINNING.

' No. 883,500. I Original application filed November 29,

Specification oi'. Letters Patent.

Patented March 31, 1.908.

seria No, 351,403.

To all whom it may concern:

Be it known that I, ELMER A. SPEBRY, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented new and useful Improvements in Methods ofDetinning, of which the 'followin is a specification.

My invention re ates to a process for detinni'ng-` tin scrap, cuttings or waste tin plate, l and itconsis'ts, broadly speaking, in treating such scrap with chlorin or chlorin compounds under conditions designed to secure' themost 'effective and complete removal and recovery of the Vtin from such scrap either as tin or tin compounds.

lt also consistsin the preliminary treatment of the scrap and in various steps of treatment of both scra and product throughout the o eration of t e process, all of whichv are pecu 'ar to my process, and which are and pointed out in the claims attached hereto and forin-` inga part hereof. l

' The accompanying drawings serve for puose of illustrating one form of apparatus wit which the processmay be carried into edect. I

In these drawings Fi one lialf (71A) basket.

e 1, illustrates a 2 is two half .baskets assembled into a spherical packagp. e

Fig. 3 represents a diagrammatic view of t ste sof the process. U

efore going into a detailed description be well to explain that 'possible or" all other foreign metals, inasmuchas scrap containing more than .04 per cent: of ioreignlmetal is unfit for 'purposes of making and therefore of very little value as there is practically no market` for impure scrap. Again the surface ofthe scrap should be attacked or oxidized as little as possible. Again, the process should be as continuous as practicable, in this manner avoiding unnecessary expense for'labor. l

In thevv preliminary pre aration of the it may `be divided into two classes; which is usually from new tin plate, and manufactured sera which is for the most art old scrap, suc i as cans, etc. The rst c ass is put into the retainers or baskets direct. The second class may have revious laced intot ese bas- Aused consists first in cuttings,

employe'd'is a Vdevice similar t ing for melting solder and weakening joints. Third, While hot',l disrnembering and opening all joints. The last process bei preferably done with such violence as toxtr solder possible, which is recovered. This scrap is then placed in half baskets indicated by A and A, which are then brought to gether in the form of a sphere as indicated by A, Fig. 2x

The baskets are practically made of steel net or wires A meridianally. .disposed and' secured to a circular ring at the ]oint. The rings are detachably secured toeach other. The tin scrap orcuttings are now preferably WashedV in a bath of caustic alkalilin tank B, drained and dried in oven D, whereupon they .a rough mechanical classification; then heat- Y ow on all are in readiness to join the other baskets in wise causin motion to be imparted'to these spheres in' t eir transit through the various stages of process. One means that may be a hollow revolving screen which is slightly inclined from end. to end, u on the revolving'of which the s heres intro uced at one end graduall work t eii' way to the other, While constant y preall their various surfaces and facesy senting to the action and also after having rotated in ractically every plane ossible.-

he rotation is valuable om the fact that especially in somebf the steps of the process, such for instance, as drying and evaporating, the universal motion imparted lserves to dump and eject any material which would' otherwise be trap ed and retained in an angle or corner o the scrap as packed or compacted. These revolving screens may be made of iron inasmuch as under the conditions here presented, iron is not attacked by the chemical used in the reactions. v thel baskets are dried' and referably while yet hot, they are introduced om the furnace D into the tube E of the vessel E, in which is a revolving screen a, handling thev spheres A, A, A, etc., below the surface-of the detinning agent C.

In am liiication of the above statements and to still further point out the nature and results of the above described preliminary treatment ofthescra be called to some fur-t er considerations with number of clevices may b e employed for rolling or other- After` attention should iirst.

I regard tothe character of the scrap,y and particularly the character of the manufactured Scrap under consideration.

lIt is known that the first class of scrap pointed out above,whi ch consists in trimmingscuttings, punch press skeletons, etc., does not constitute'more thanS to 9 ofthe total tin plate utilized in the manufacture of tins and tin plate articles. In many cases Where rectangular shapes are employed, such as square cans, can-bodiesand similarstructures, the percentage of trimmings including above.

the listed edges of the sheets constitute a much smaller 4percentage than that named It is a well known fact that ultimately all or nearly all of the manufactured articles from tin plate deteriorate and are discarded and thus become scrap of the second l class named above, and it will also be seen from the percentages discussed, that this class of scrap constitutes by far the most important body to be' dealt with in the process of detinning. f

Manufactured scrap as such, While it constitutes the largest body, also constitutes the most difficult class to deal with in-connection with the detinning processes.- Some of the detinning, and one w ich is difiicult to climinate owing to the fact that it is conned in the seams and lock-.jomts .of thecans and containers 1n a manner rendering its removal difficult. Again, a few cans, and containers,

in this country are beginning to appear with aplastic layer rolled and crimped within the. en'd seams of the can, which it isnecessary to vremove in order to allow fullaccess of the deremoving the tin. These plastic rings .or

tinningchemicals and. re-agents employed in layers are made up from organic materials, consisting usually of some form ofcarbohydrate associated with gelatin and` formaldehyde. Sometimes parchmentized fiber or fabric yis used in and about these jointsI and in isolated cases, gum such asrubber is employed. Regardless of the nature `'of ,these joint fillers, they should be removed and the s aces employed for admission :of the active etinning agent. Furthermore, litfis necessary that in the steps of preliminary treatment of the scrap prior to detinning, thev various substances found to.l be associated vwitlrthe steel other than the tin, shouldbe *,converted into a state or into a' product that 'willbe inert.' towards the activeagentsemv liminary treatment of the scrap, it is the.

object of the present application to more fully amplify the said preliminary treatment and the steps involved therein, together with materials employed and manipulations involved in such steps of the process. The

detinning process which succeeds this treatment may be of any nature, such as' the alkaline electrolytic process or the acid process, but the preparation herewith described especially fits the lold or manufactured scrap, articles, etc, for chlorin detinning and it isv this process which is described and claimed in my prior application, of which this is a division as stated. It is well known that much of the lac uer, varnish, .paint and-special lac uer suci as is -used to line sardine cans, wiich is made to withstand especially high temperatures, While they will withstand acids, steaming, soda solutions and the like, will not withstand caustic alkali of either the sodium or potassium bases, especial ly when the solution of either of these salts is applied at an elei v' the operation vated temperature. Thus largely involving a saponification of the filth and adhering matters, impurities, etc., the scrap becomes free or partially free from these materials and the resulting mass, aside from being subjected to the high temperatures in furnace D, are converted into forms which are inert toward chlorinor any of the chlorin compounds-employed in succeeding steps of the process of detinning proper.

As indicated above, scrap may be taken in bulkbefore being packed into baskets A, made up from the filled half-baskets A but f find that these spheresfowing to the ease Withwhich they may be moved about and agitated, yield lbett-er results on the whole ,than where the treatmentis undertaken in bulk. After being filled and compacted to a more or less degree as stated, these spheres of scrap are introduced intank B into one 2 end ofthe revolving erforated cylinder t1, therein, which by simp e revolution upon its axis, causes the spheres to move and owing to the slight inclination of the axis as indicated in the irevolving cylinder a, ournaled at c and a, the baskets are continually rolling or attem ting to roll' toward one end, which givest em a universal motion so that all arts arefex osed'as described. After the' baskets have een-subjected to this treatment for sufficient length'of timev to remove and saponify the impurities, many of Which are found to be quitefully removed b "this operation, they are removed to a simi ar treating tank C, where the identical mechanism is shown as being employed, Where they 'are first drained from the alkaline solution. which is then drawn-off from wherein they are-flushed or rinsed, preferin readiness. for the furnace D. This furnace is supplied with a chimney D; practically identical revolving drum mechanism With the other tanks, and may also be supplied With-an inner inclosure D, outside of which is the fire-boi; D3, supplied by the oil or other burner D4. If the in'closure D is used, a separate vent D5 is employed therefor, as indicated'inthe drawing. The sphere A of scrap is shown Within the revolving drum. The -scrap after being drained and preferably rinsed and. drained in tanks A', is brought to 'a temperature in the oven or furnace D, suitable for melting the solder and' weakening the joints and dismemberinv, through the j olting and agitation of the rolling spheres as Well as through the sudden expansion of the parts. lfV not entirely dismembered, the joints are so loosened bythe removal of the solder or charring or burnin f out'of thel plastic mass used as a joint iller. so that they are Well edited to the detinninf. process which immediately follows. The eat here is raised to a point Where these operations are found to. have been accomplished. It will be understood that the inclosure D may .be employed for exclusion of oxidizing gases, especially Where the temperatures are excessive, but owing to the fact that tin isl not an easily oxidized material, I do not :nd the exclusion of corrosive gases'to be extremely essential. It maybe consideredlthat for orv.\dinary purposes, a temperature of 350 to 500 centigrade Will be sufficient, but to'accelerate the 'pe'ration the furnace may be held at a point considerably higher and the baskets putthrough `more rapidly. This is found to char, shrivel or deteriorate even the l most obstinate and refractory materials and when used in the joints and inclosed in the folds of the joints, or such folds as may accidentally occur when the scrap is considerably mutilated and jammed or crushed. Most of f these materials are vola-tilized, the gases escaping through chimney DKor D5, dependent upon the presence or absence of the inclosure D.

It may be understood drums in each of the cases foratedl and that the solder which is`very that the revolving described are periluid at tlen high temperatures, flows away from the scrap through"thbasket and accumulates in the bottom of the furnace be- 4acaso() j low the llame or in theiinclosure D.

further be understood that excessive temperatures should be guardedI against', as if the temperature is too high, thev tin upon the surface will be alloy'ed with the iron, as is well understood, and the scrap rendered unfit for det-inning or other purposes. 0n the other hand, too low temperatures, the fluxing of the solder is only partial, preventing itsy free escape from' the joints and dislodgment, Whereas when' the proper temperature is reached, the solder flows freely and through the agitation and complex movements vof the baskets, the contents may be easily expelled Without spreading over the surfaces of the scrap and gin at any particular distance from the joint.

cra is a owed to cool down t-o a certain degree before being introduced into the detinning process roper, which is illustrated in the drawing y tank AE and furnace with a large tube E', into which the scrap While yethot is introduced.' It is not necessary to describe the successi y,e steps relating to the removal of the tin from the scrap as this has been fully described and claimed in my rior application referred to above. `It may, owever, be Well to say that the basketsv A are into the jacketed pipe G, preferably in the presence of anhydrous stannic chlorid c,

surface of which the baskets are submerged, the same mechanism, consisting of the revolving perforated drum a, being utilized, and it is the object and impurities inerttoward both the chlorin and the stannic chlorid. Incidentally it ma be's'tated that lead as such is inert tovvard'botlil of these materials.

It will readily the details of the processes may be varied v ing from the essence of the invention.

1. The method of preparing tin scrap, associated in part with tinning which consists` `in classifying this scrap, subjecting one ofthe classes to a saponlfying solution and to high temperature, ringing the classes together and introducing them jointly to the detinning process.

2. The method of preparingtin scrap, associated in part with foreign matter, for detinningwhich consists in classifying this scrap, subjecting one of the classes to a sa.;

onlfying solution andto high temperature,

and introducing them jointly to the detinning rocess While still-in a heated state.

sociatedwith foreign matter for anhy rous alloying With the subjected to the action of chlorin introduced.

which here shown in a body beneath the be understood that some of i he method of preparing tin scr-'a assubjected to the treatment described roo of the treatment described in detail. herein, to render the filthand some of the steps altered without depart- .I

foreign matter, for dermginglthe classes together, heatmg same v `sociated with foreign matter whic consists .30 eliminating that part not so rein ved, ren- 4 @eases detinnmg whic-h consists in cleaning and solution and to high temperatures while unhighly heating the scrap and then while. 'hot der conditions of motion or agitation, presubjecting it to the detinning process proper. paratory to detinning.

4. The method of preparing tin scrap/as- 8. The method of preparing tin scrap, as- 40 5 sociated with foreign matter, which consists sociated with foreign matter, which consists in subjecting such scrap to treatment in asoin packing the scrap into bundles, subjecting lu'tionfor cleansing same,the soluticnliormed such bundles successively to a saponifying from a substance not removable by the subsolution and to high temperatures while un- Tsequent heating step in the process, treating der conditions oi motion or agitation in each 10 the scrap for removal of `such substance and step, preparatoryto detinning.- f also to a high temperature prepajatory to' '9. The method of preparing tin scrap, asdetinning. j l sociated with foreign matter for anhydrous 5. The method of preparing tin?)` crap asdetinning, which `consists in subjecting such l scrap to a high temperature and then to the anhydrous detinning process while still in a heated state. j

l0. The method of preparing tin scra associated with foreign matter for anhy reus detinning which consists in bundling thescrap and subjecting such bundles to a high temperature fand then to the detinning process proper while still in a heated state.

l1. The method oi preparing tin scrap as'- sociated with Vforeign matter which consists in bundling the scrap, cleaning and highly heating such scrap in a gaseous medium for drying same, and then while hot subjecting the bundles to the detinning process proper,

In testimony whereof l have hereunto set my hand in presence of two subscribing wit-l nesses. l

15 xinfsubjecting .su/ch scrap to treatment in a solution for cleansing same, the 'solution formed from a substance not removable by the subse uent heating step in theprocess, mechanica ly cooling or draining they sub- 20 stance from the scrap, then treating the scrap for removal of suchsubstance. andl also to a high temperature preparatory to detinning.

6. The methodof' preparing tiny scrap associated .with foreign matter for detinning,

2.5 which consists in subjecting such scrap succes'sivelyjto a saponif'ying solution, a washing or rinsing process Jfor the removal t lution andat a tem erature suiic'i' removal of some ot the foreign'r a tter and dering it inert to the detinning 'agent employed. l, 7. The' method of preparing tin scrap, as j sociated with Jforeign matter, which consists litnesses:

35 in packing the scrap into bundles, subjecting WILLIAM F. BUTTON,

vsuch -bundles successively to a saponiying L. A. WELLES.

-ELMER A. SPERRY. 

